1. Field of the Invention
The present invention relates to a digital TV receiver, and more particularly, to a method for changing channel information in a digital TV receiver.
2. Background of the Related Art
Recently, keeping pace with development on TV technologies, there has been growing interests in digital TV receivers having a digital transmission system applied thereto, and, in a domestic case, the Mugungwha satellite was launched and started digital test broadcasting in July '96. In general, a time multiplexed signal of video, audio and program specific information signals intended to transmit in a digital satellite broadcasting is called as a transport stream(TS), which is QPSK modulated before transmission to respective receivers through a satellite.
Referring to FIG. 1, in detail, the information multiplexed to TS has an elementary stream of which main purpose is broadcasting, and a RSMS(Resource & Subscriber Management System) stream, a program specific information. The elementary stream is inclusive of video information, and audio information the same as the analog broadcasting, and data additional in a case of the digital broadcasting. The RSMS stream has SI(Service Information) and RSMS message, of which RSMS message is transmitted in a case when a conditional access function is used, and the SI has PSI(Program Specific Information) which allows a receiver to demultiplex the TS and PMM(Program Guide Message). The PSI, which is an objective of the present invention, has PAT(Program Association Table), PMT(Program Map Table) and CAT (Conditional Access Table).
FIG. 2 illustrates a PSI table, wherein the PAT provides PIDs(Packet IDs) of the PMT connecting program numbers which is information on a service stream provided presently, i.e., information on assignment of channels to repeaters to the elementary stream having video and audio information for each program number, and PIDs of the PMM and the RCM in the RSMS stream. The PMT provides a program definition by connecting the program number to one set of elementary stream. One section of the PMT defines one program.
The PAT and PMT have architectures as shown in FIGS. 3a and 3b respectively. The PAT has a data pattern inclusive of a version number which is increased as a number of PMT sections is increased and decreased as the number of PMT sections is decreased, i.e., broadcasting channel changes in correspondence to the PMT section. A related art digital TV receiver conducts PAT and PMT parsing only when an initial power is turned on for re-setting channel information and, maintains broadcasting channel information set initially until turning on after turning off the power. Because the related art digital TV receiver maintains a channel set at initial power supply as it is during watching a broadcasting, the related art digital TV receiver has a problem in that a channel having no display of video can not be canceled or a channel added newly can not be displayed even if channel information is changed due to channel cancellation/addition during broadcasting, that gives inconvenience to users.